CVE-2026-26861 - Vulnerability Analysis

Overview

CleverTap Web SDK <= 1.15.2 contains a stored XSS caused by insufficient origin validation in handleCustomHtmlPreviewPostMessageEvent using includes() in src/util/campaignRender/nativeDisplay.js, letting attackers execute scripts via crafted postMessage, exploit requires attacker to send crafted postMessage from a subdomain.

Severity & Score

Impact

Attackers can execute arbitrary scripts in users' browsers, leading to session hijacking or data theft.

Mitigation

Update to a version later than 1.15.2 or the latest available version.

References

• https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121
• https://github.com/CleverTap/clevertap-web-sdk/issues/424
• https://github.com/CleverTap/clevertap-web-sdk/pull/417

Related Resources

• Vulnerability Intelligence Dashboard
• Credential Scanner